linux/net/sched/act_ipt.c
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   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * net/sched/act_ipt.c          iptables target interface
   4 *
   5 *TODO: Add other tables. For now we only support the ipv4 table targets
   6 *
   7 * Copyright:   Jamal Hadi Salim (2002-13)
   8 */
   9
  10#include <linux/types.h>
  11#include <linux/kernel.h>
  12#include <linux/string.h>
  13#include <linux/errno.h>
  14#include <linux/skbuff.h>
  15#include <linux/rtnetlink.h>
  16#include <linux/module.h>
  17#include <linux/init.h>
  18#include <linux/slab.h>
  19#include <net/netlink.h>
  20#include <net/pkt_sched.h>
  21#include <linux/tc_act/tc_ipt.h>
  22#include <net/tc_act/tc_ipt.h>
  23
  24#include <linux/netfilter_ipv4/ip_tables.h>
  25
  26
  27static unsigned int ipt_net_id;
  28static struct tc_action_ops act_ipt_ops;
  29
  30static unsigned int xt_net_id;
  31static struct tc_action_ops act_xt_ops;
  32
  33static int ipt_init_target(struct net *net, struct xt_entry_target *t,
  34                           char *table, unsigned int hook)
  35{
  36        struct xt_tgchk_param par;
  37        struct xt_target *target;
  38        struct ipt_entry e = {};
  39        int ret = 0;
  40
  41        target = xt_request_find_target(AF_INET, t->u.user.name,
  42                                        t->u.user.revision);
  43        if (IS_ERR(target))
  44                return PTR_ERR(target);
  45
  46        t->u.kernel.target = target;
  47        memset(&par, 0, sizeof(par));
  48        par.net       = net;
  49        par.table     = table;
  50        par.entryinfo = &e;
  51        par.target    = target;
  52        par.targinfo  = t->data;
  53        par.hook_mask = hook;
  54        par.family    = NFPROTO_IPV4;
  55
  56        ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
  57        if (ret < 0) {
  58                module_put(t->u.kernel.target->me);
  59                return ret;
  60        }
  61        return 0;
  62}
  63
  64static void ipt_destroy_target(struct xt_entry_target *t, struct net *net)
  65{
  66        struct xt_tgdtor_param par = {
  67                .target   = t->u.kernel.target,
  68                .targinfo = t->data,
  69                .family   = NFPROTO_IPV4,
  70                .net      = net,
  71        };
  72        if (par.target->destroy != NULL)
  73                par.target->destroy(&par);
  74        module_put(par.target->me);
  75}
  76
  77static void tcf_ipt_release(struct tc_action *a)
  78{
  79        struct tcf_ipt *ipt = to_ipt(a);
  80
  81        if (ipt->tcfi_t) {
  82                ipt_destroy_target(ipt->tcfi_t, a->idrinfo->net);
  83                kfree(ipt->tcfi_t);
  84        }
  85        kfree(ipt->tcfi_tname);
  86}
  87
  88static const struct nla_policy ipt_policy[TCA_IPT_MAX + 1] = {
  89        [TCA_IPT_TABLE] = { .type = NLA_STRING, .len = IFNAMSIZ },
  90        [TCA_IPT_HOOK]  = { .type = NLA_U32 },
  91        [TCA_IPT_INDEX] = { .type = NLA_U32 },
  92        [TCA_IPT_TARG]  = { .len = sizeof(struct xt_entry_target) },
  93};
  94
  95static int __tcf_ipt_init(struct net *net, unsigned int id, struct nlattr *nla,
  96                          struct nlattr *est, struct tc_action **a,
  97                          const struct tc_action_ops *ops, int ovr, int bind,
  98                          struct tcf_proto *tp, u32 flags)
  99{
 100        struct tc_action_net *tn = net_generic(net, id);
 101        struct nlattr *tb[TCA_IPT_MAX + 1];
 102        struct tcf_ipt *ipt;
 103        struct xt_entry_target *td, *t;
 104        char *tname;
 105        bool exists = false;
 106        int ret = 0, err;
 107        u32 hook = 0;
 108        u32 index = 0;
 109
 110        if (nla == NULL)
 111                return -EINVAL;
 112
 113        err = nla_parse_nested_deprecated(tb, TCA_IPT_MAX, nla, ipt_policy,
 114                                          NULL);
 115        if (err < 0)
 116                return err;
 117
 118        if (tb[TCA_IPT_INDEX] != NULL)
 119                index = nla_get_u32(tb[TCA_IPT_INDEX]);
 120
 121        err = tcf_idr_check_alloc(tn, &index, a, bind);
 122        if (err < 0)
 123                return err;
 124        exists = err;
 125        if (exists && bind)
 126                return 0;
 127
 128        if (tb[TCA_IPT_HOOK] == NULL || tb[TCA_IPT_TARG] == NULL) {
 129                if (exists)
 130                        tcf_idr_release(*a, bind);
 131                else
 132                        tcf_idr_cleanup(tn, index);
 133                return -EINVAL;
 134        }
 135
 136        td = (struct xt_entry_target *)nla_data(tb[TCA_IPT_TARG]);
 137        if (nla_len(tb[TCA_IPT_TARG]) != td->u.target_size) {
 138                if (exists)
 139                        tcf_idr_release(*a, bind);
 140                else
 141                        tcf_idr_cleanup(tn, index);
 142                return -EINVAL;
 143        }
 144
 145        if (!exists) {
 146                ret = tcf_idr_create(tn, index, est, a, ops, bind,
 147                                     false, 0);
 148                if (ret) {
 149                        tcf_idr_cleanup(tn, index);
 150                        return ret;
 151                }
 152                ret = ACT_P_CREATED;
 153        } else {
 154                if (bind)/* dont override defaults */
 155                        return 0;
 156
 157                if (!ovr) {
 158                        tcf_idr_release(*a, bind);
 159                        return -EEXIST;
 160                }
 161        }
 162        hook = nla_get_u32(tb[TCA_IPT_HOOK]);
 163
 164        err = -ENOMEM;
 165        tname = kmalloc(IFNAMSIZ, GFP_KERNEL);
 166        if (unlikely(!tname))
 167                goto err1;
 168        if (tb[TCA_IPT_TABLE] == NULL ||
 169            nla_strscpy(tname, tb[TCA_IPT_TABLE], IFNAMSIZ) >= IFNAMSIZ)
 170                strcpy(tname, "mangle");
 171
 172        t = kmemdup(td, td->u.target_size, GFP_KERNEL);
 173        if (unlikely(!t))
 174                goto err2;
 175
 176        err = ipt_init_target(net, t, tname, hook);
 177        if (err < 0)
 178                goto err3;
 179
 180        ipt = to_ipt(*a);
 181
 182        spin_lock_bh(&ipt->tcf_lock);
 183        if (ret != ACT_P_CREATED) {
 184                ipt_destroy_target(ipt->tcfi_t, net);
 185                kfree(ipt->tcfi_tname);
 186                kfree(ipt->tcfi_t);
 187        }
 188        ipt->tcfi_tname = tname;
 189        ipt->tcfi_t     = t;
 190        ipt->tcfi_hook  = hook;
 191        spin_unlock_bh(&ipt->tcf_lock);
 192        return ret;
 193
 194err3:
 195        kfree(t);
 196err2:
 197        kfree(tname);
 198err1:
 199        tcf_idr_release(*a, bind);
 200        return err;
 201}
 202
 203static int tcf_ipt_init(struct net *net, struct nlattr *nla,
 204                        struct nlattr *est, struct tc_action **a, int ovr,
 205                        int bind, bool rtnl_held, struct tcf_proto *tp,
 206                        u32 flags, struct netlink_ext_ack *extack)
 207{
 208        return __tcf_ipt_init(net, ipt_net_id, nla, est, a, &act_ipt_ops, ovr,
 209                              bind, tp, flags);
 210}
 211
 212static int tcf_xt_init(struct net *net, struct nlattr *nla,
 213                       struct nlattr *est, struct tc_action **a, int ovr,
 214                       int bind, bool unlocked, struct tcf_proto *tp,
 215                       u32 flags, struct netlink_ext_ack *extack)
 216{
 217        return __tcf_ipt_init(net, xt_net_id, nla, est, a, &act_xt_ops, ovr,
 218                              bind, tp, flags);
 219}
 220
 221static int tcf_ipt_act(struct sk_buff *skb, const struct tc_action *a,
 222                       struct tcf_result *res)
 223{
 224        int ret = 0, result = 0;
 225        struct tcf_ipt *ipt = to_ipt(a);
 226        struct xt_action_param par;
 227        struct nf_hook_state state = {
 228                .net    = dev_net(skb->dev),
 229                .in     = skb->dev,
 230                .hook   = ipt->tcfi_hook,
 231                .pf     = NFPROTO_IPV4,
 232        };
 233
 234        if (skb_unclone(skb, GFP_ATOMIC))
 235                return TC_ACT_UNSPEC;
 236
 237        spin_lock(&ipt->tcf_lock);
 238
 239        tcf_lastuse_update(&ipt->tcf_tm);
 240        bstats_update(&ipt->tcf_bstats, skb);
 241
 242        /* yes, we have to worry about both in and out dev
 243         * worry later - danger - this API seems to have changed
 244         * from earlier kernels
 245         */
 246        par.state    = &state;
 247        par.target   = ipt->tcfi_t->u.kernel.target;
 248        par.targinfo = ipt->tcfi_t->data;
 249        ret = par.target->target(skb, &par);
 250
 251        switch (ret) {
 252        case NF_ACCEPT:
 253                result = TC_ACT_OK;
 254                break;
 255        case NF_DROP:
 256                result = TC_ACT_SHOT;
 257                ipt->tcf_qstats.drops++;
 258                break;
 259        case XT_CONTINUE:
 260                result = TC_ACT_PIPE;
 261                break;
 262        default:
 263                net_notice_ratelimited("tc filter: Bogus netfilter code %d assume ACCEPT\n",
 264                                       ret);
 265                result = TC_ACT_OK;
 266                break;
 267        }
 268        spin_unlock(&ipt->tcf_lock);
 269        return result;
 270
 271}
 272
 273static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind,
 274                        int ref)
 275{
 276        unsigned char *b = skb_tail_pointer(skb);
 277        struct tcf_ipt *ipt = to_ipt(a);
 278        struct xt_entry_target *t;
 279        struct tcf_t tm;
 280        struct tc_cnt c;
 281
 282        /* for simple targets kernel size == user size
 283         * user name = target name
 284         * for foolproof you need to not assume this
 285         */
 286
 287        spin_lock_bh(&ipt->tcf_lock);
 288        t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC);
 289        if (unlikely(!t))
 290                goto nla_put_failure;
 291
 292        c.bindcnt = atomic_read(&ipt->tcf_bindcnt) - bind;
 293        c.refcnt = refcount_read(&ipt->tcf_refcnt) - ref;
 294        strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name);
 295
 296        if (nla_put(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t) ||
 297            nla_put_u32(skb, TCA_IPT_INDEX, ipt->tcf_index) ||
 298            nla_put_u32(skb, TCA_IPT_HOOK, ipt->tcfi_hook) ||
 299            nla_put(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c) ||
 300            nla_put_string(skb, TCA_IPT_TABLE, ipt->tcfi_tname))
 301                goto nla_put_failure;
 302
 303        tcf_tm_dump(&tm, &ipt->tcf_tm);
 304        if (nla_put_64bit(skb, TCA_IPT_TM, sizeof(tm), &tm, TCA_IPT_PAD))
 305                goto nla_put_failure;
 306
 307        spin_unlock_bh(&ipt->tcf_lock);
 308        kfree(t);
 309        return skb->len;
 310
 311nla_put_failure:
 312        spin_unlock_bh(&ipt->tcf_lock);
 313        nlmsg_trim(skb, b);
 314        kfree(t);
 315        return -1;
 316}
 317
 318static int tcf_ipt_walker(struct net *net, struct sk_buff *skb,
 319                          struct netlink_callback *cb, int type,
 320                          const struct tc_action_ops *ops,
 321                          struct netlink_ext_ack *extack)
 322{
 323        struct tc_action_net *tn = net_generic(net, ipt_net_id);
 324
 325        return tcf_generic_walker(tn, skb, cb, type, ops, extack);
 326}
 327
 328static int tcf_ipt_search(struct net *net, struct tc_action **a, u32 index)
 329{
 330        struct tc_action_net *tn = net_generic(net, ipt_net_id);
 331
 332        return tcf_idr_search(tn, a, index);
 333}
 334
 335static struct tc_action_ops act_ipt_ops = {
 336        .kind           =       "ipt",
 337        .id             =       TCA_ID_IPT,
 338        .owner          =       THIS_MODULE,
 339        .act            =       tcf_ipt_act,
 340        .dump           =       tcf_ipt_dump,
 341        .cleanup        =       tcf_ipt_release,
 342        .init           =       tcf_ipt_init,
 343        .walk           =       tcf_ipt_walker,
 344        .lookup         =       tcf_ipt_search,
 345        .size           =       sizeof(struct tcf_ipt),
 346};
 347
 348static __net_init int ipt_init_net(struct net *net)
 349{
 350        struct tc_action_net *tn = net_generic(net, ipt_net_id);
 351
 352        return tc_action_net_init(net, tn, &act_ipt_ops);
 353}
 354
 355static void __net_exit ipt_exit_net(struct list_head *net_list)
 356{
 357        tc_action_net_exit(net_list, ipt_net_id);
 358}
 359
 360static struct pernet_operations ipt_net_ops = {
 361        .init = ipt_init_net,
 362        .exit_batch = ipt_exit_net,
 363        .id   = &ipt_net_id,
 364        .size = sizeof(struct tc_action_net),
 365};
 366
 367static int tcf_xt_walker(struct net *net, struct sk_buff *skb,
 368                         struct netlink_callback *cb, int type,
 369                         const struct tc_action_ops *ops,
 370                         struct netlink_ext_ack *extack)
 371{
 372        struct tc_action_net *tn = net_generic(net, xt_net_id);
 373
 374        return tcf_generic_walker(tn, skb, cb, type, ops, extack);
 375}
 376
 377static int tcf_xt_search(struct net *net, struct tc_action **a, u32 index)
 378{
 379        struct tc_action_net *tn = net_generic(net, xt_net_id);
 380
 381        return tcf_idr_search(tn, a, index);
 382}
 383
 384static struct tc_action_ops act_xt_ops = {
 385        .kind           =       "xt",
 386        .id             =       TCA_ID_XT,
 387        .owner          =       THIS_MODULE,
 388        .act            =       tcf_ipt_act,
 389        .dump           =       tcf_ipt_dump,
 390        .cleanup        =       tcf_ipt_release,
 391        .init           =       tcf_xt_init,
 392        .walk           =       tcf_xt_walker,
 393        .lookup         =       tcf_xt_search,
 394        .size           =       sizeof(struct tcf_ipt),
 395};
 396
 397static __net_init int xt_init_net(struct net *net)
 398{
 399        struct tc_action_net *tn = net_generic(net, xt_net_id);
 400
 401        return tc_action_net_init(net, tn, &act_xt_ops);
 402}
 403
 404static void __net_exit xt_exit_net(struct list_head *net_list)
 405{
 406        tc_action_net_exit(net_list, xt_net_id);
 407}
 408
 409static struct pernet_operations xt_net_ops = {
 410        .init = xt_init_net,
 411        .exit_batch = xt_exit_net,
 412        .id   = &xt_net_id,
 413        .size = sizeof(struct tc_action_net),
 414};
 415
 416MODULE_AUTHOR("Jamal Hadi Salim(2002-13)");
 417MODULE_DESCRIPTION("Iptables target actions");
 418MODULE_LICENSE("GPL");
 419MODULE_ALIAS("act_xt");
 420
 421static int __init ipt_init_module(void)
 422{
 423        int ret1, ret2;
 424
 425        ret1 = tcf_register_action(&act_xt_ops, &xt_net_ops);
 426        if (ret1 < 0)
 427                pr_err("Failed to load xt action\n");
 428
 429        ret2 = tcf_register_action(&act_ipt_ops, &ipt_net_ops);
 430        if (ret2 < 0)
 431                pr_err("Failed to load ipt action\n");
 432
 433        if (ret1 < 0 && ret2 < 0) {
 434                return ret1;
 435        } else
 436                return 0;
 437}
 438
 439static void __exit ipt_cleanup_module(void)
 440{
 441        tcf_unregister_action(&act_ipt_ops, &ipt_net_ops);
 442        tcf_unregister_action(&act_xt_ops, &xt_net_ops);
 443}
 444
 445module_init(ipt_init_module);
 446module_exit(ipt_cleanup_module);
 447